1. Field of the Invention
The present invention relates to an indwelling needle assembly to be used to puncture a blood vessel and be left indwelling there, in the case of an infusion, for example.
2. Description of the Related Art
At the time of carrying out an infusion on a patient or in other similar situations, an indwelling needle to be connected with an infusion line is made to puncture a patient's blood vessel and is left indwelling for performing the infusion.
Such an indwelling needle assembly, normally, includes a hollow outer needle, an outer needle hub secured to a base end (proximal end) of the outer needle, an inner needle which is inserted into the outer needle and which has a sharp needle point at a tip (distal end) thereof, an inner needle hub secured to a base end (proximal end) of the inner needle, and a protector which is detachably coupled to the outer needle hub. The outer needle hub is formed with a main pipe having a flow path communicating with the lumen of the outer needle, and a side pipe having a branch flow path branched from the flow path in the main pipe, wherein an infusion line is to be connected to the side pipe (see, for example, U.S. Pat. No. 6,749,588).
At the time of puncturing a patient's blood vessel with the indwelling needle, a puncturing operation is conducted in an assembled condition wherein the inner needle is inserted into the outer needle and the needle point of the inner needle protrudes from the tip (distal end) of the outer needle.
When the needle point of the inner needle has reached the inside of the blood vessel, blood flows into the inner needle through its distal portion, the blood, in its course of flowing, flows through a hole formed in a side portion of the inner needle into a flow path between the outer needle and the inner needle, then flows through the flow path into the inside of the transparent outer needle hub, that is, into the flow path in the main pipe and, further, flows from the main pipe into the branch flow path in the side pipe (flashback). This permits a clinician (user) to confirm (visually recognize) that the inner needle has captured (securely punctured) the blood vessel.
After flashback is confirmed, the outer needle is advanced using the inner needle as a guide, and the outer needle is made to puncture the blood vessel.
Next, while fixing the outer needle or the outer needle hub by holding it by one hand, the inner needle hub is held by the other hand and moved in the proximal direction, to draw the inner needle out of the outer needle. Then, an infusion agent is administered through the connected infusion line, the side pipe of the outer needle hub, the main pipe of the outer needle hub, and the outer needle.
Meanwhile, at the time of putting the outer needle of the indwelling needle assembly indwelling in a patient, the clinician (user) wears gloves, holds the indwelling needle assembly with fingers of the gloved hand, and performs the puncturing operation. In the case of the puncturing operation, the clinician may hold the indwelling needle assembly by a method as shown in FIG. 3, for example.
This holding method is herein referred to as “wing port holding.” In this holding method, the thumb is put in contact with the proximal end of the inner needle hub, whereas one of the remaining fingers, for example, the middle finger is put in contact with the distal side of the indwelling needle assembly, specifically, a wing of the outer needle hub, whereby the indwelling needle assembly is held so as to be pinched in the longitudinal direction thereof.
In an indwelling needle assembly according to the related art, however, fingers of a gloved hand are liable to slip relative to the indwelling needle assembly at the time of a puncturing operation. Particularly, the thumb is liable to slip off a base portion (proximal portion) of the inner needle hub, which makes the puncturing operation difficult to achieve.